$do_ranks = array(
  'sa' => 'sa_rank',
  'da' => 'da_rank',
  'spy' => 'spy_rank',
  'sentry' => 'sentry_rank',
  'thief' => 'thief_rank',
  'sa_rank+da_rank+spy_rank+sentry_rank+thief_rank' => 'rank'
);

foreach( $do_ranks as $order_by => $column ) {
  mysql_query( 'TRUNCATE TABLE ranks' )
  && mysql_query( 'INSERT INTO ranks(id) SELECT id '
    . 'FROM members_data ORDER BY ' . $order_by . ' DESC' )
  && mysql_query( 'UPDATE members_data LEFT JOIN ranks USING(id) '
    . 'SET ' . $column . ' = rank_id' );
}

mysql_query( 'TRUNCATE TABLE ranks' );